Kaboom!

You must have a Trapper skill of 8 or higher before you can complete this quest.

Check the New Ashos bulletin board for the scroll that starts "Kaboom!" Grab the hidden Hell Unleashed bombs from the cemetery east of town, then head northwest to the hidden warehouse. You must use these bombs to blow up the three Guardians on patrol around the warehouse; killing them in any other way is a failure condition.

Fortunately, you don't have to sneak up and plant the bombs directly over their patrol route. You can drop a bomb wherever you like, then bounce a weak arrow off a Guardian's head to get it to run over to you. Just be careful that you're not caught in the explosion radius.

Your reward, back in the chest by the bulletin board in New Ashos, consists of 200 auras, four Hell Unleashed bombs of your own, two lockpicks, and another Warlord, that weak club from the introductory chapter. I'm not sure what that last one's doing here.